1. Field of the Invention
The present invention is directed to a universal joint assembly and more particularly to the body and a trunnion assembly thereof. The trunnion assembly comprises a plurality of trunnion pins rotationally mounted on the body, thereby eliminating the need for interconnecting bearing assemblies typically used to pivotally interconnect bifurcated yokes of associated rotary axles or shafts, in a conventional manner.
2. Description of the Related Art
Universal joints are well known and find a primary field of use in interconnecting drive line components of motor vehicles. More specifically, universal joints are conventionally used to interconnect a pair of rotary shafts or axles in a manner which permits both rotational and relative pivotal motion of the connected shafts. Typically, universal joints include or are associated with two bifurcated yokes each of which are secured to a corresponding end of one of the rotary axles or shafts being interconnected. Relative pivotal interconnection of the yokes to one another is accomplished by the body of the universal joint, commonly referred to as a spider or cruciform, including a plurality of fixedly attached, orthogonally oriented trunnions.
Axially aligned ones of the plurality of trunnions define a trunnion pair which are connected within apertures formed in the spaced apart legs of the bifurcated yokes. In the conventional design and structuring of a universal joint, a bearing assembly which may include a plurality of needle bearings or structurally equivalent bearings are arranged in a bearing retainer. The aforementioned bearing assemblies serve to interconnect individual ones of the trunnions to the opposite legs of each of the yokes in order to facilitate pivotal movement of the yokes relative to the corresponding trunnion pairs.
The bearing assembly used to pivotally interconnect the individual trunnions to the corresponding yokes specifically includes the use of integrally formed grooves, washers, snap rings and other connectors to maintain the bearing assembly in place. However, it is well recognized that regardless of the various attempts to structurally retain and/or interconnect the aforementioned bearing assemblies in their operative position, various disadvantages and problems exist. Such problems include, but are not necessarily limited to, a relatively short operable life and high cost of manufacture of the bearing assemblies as well as a frequent failure of the bearing retainers.
In addition the existence of dimensional variations can exist, which frequently results in an excess clearance between the bearing assembly and the retaining structure maintaining the bearing in its operative position. Further, any resulting gap existing between the trunnions and the bearing assembly itself results in a noticeable unstable rotational and pivotal motion between the interconnected rotary axles or shafts. Accordingly, the smooth and effective transfer of torque between the two rotary shafts or axles associated with the interconnected yokes frequently becomes impossible.
Even in light of the above noted problems in unstable torque transfer and the tendency of various portions of the bearing assembly and/or the retaining connectors associated therewith to fail, there have been relatively little major advancements in the structural or operative modification of the primary components of the universal joint. Instead, advancements to overcome the above noted problems have concentrated on design improvements of the bearing assemblies, retaining structures associated therewith and/or the design of the individual needle bearings or other bearing structures used to accomplish the aforementioned pivotal interconnection.
Accordingly, there is a significant need for a universal joint assembly which is structurally unique and functionally efficient to accomplish the transfer of torque between rotary shafts while allowing relative, pivotal or angular movement therebetween. Such an improved universal joint assembly should be uniquely structured to eliminate the need for any type of bearing assembly for pivotally interconnecting the spaced apart, opposed legs of a yoke to the respective, axially oriented trunnions. Instead unique structural modifications of such an improved universal joint assembly would include rotationally securing a trunnion assembly, comprising a plurality of orthogonally oriented trunnion pins, to the body. As such the relative pivotal movement between interconnected rotary shafts could be accomplished by rotation of individual trunnion pins relative to the body, rather than by pivotal or rotational movement of the yokes of the shafts relative to the trunnion assembly, by means of the aforementioned bearing structures. Therefore, commonly recognized disadvantages and problems of the type set forth above would be substantially eliminated.
Additional structural modifications of such an improved universal joint assembly could further include the reinforcement of the cruciform body so as to eliminate or significantly restrict the possibility of flexure occurring between adjacently positioned trunnions during applications of relatively excessive force being applied to the body and trunnion assembly.